Centrifugal separators are generally used for separation of liquids and/or for separation of solids from a liquid. During operation, liquid mixture to be separated is introduced into a rotating bowl and heavy particles or denser liquid, usually water, accumulates at the periphery of the rotating bowl whereas less dense liquid accumulates closer to the central axis of rotation. This allows for collection of the separated fractions, e.g. by means of different outlets arranged at the periphery and close to the rotational axis, respectively.
The rotating bowl is usually supported by a rotating shaft, a spindle, but in certain drive system designs heat transportation and cooling of the shaft and the bearings supporting such a shaft may be problematic. Heat may for example be generated in the bearings but also in the motor stator and rotor if an electrical motor is used for rotating the shaft, and the rotor is fitted e.g. on the shaft.
In certain designs, a hollow shaft is used for supporting the bowl. In such cases, process media, such as the liquid to be separated, may be introduced to the bowl via the shaft. If the process media is cool enough and has enough flow rate, it may be enough for cooling the bearings supporting the shaft. However, there may be problems when the process media is hot, e.g. hot oil, or when there is no or a low flow through the spindle.
Well-known solutions include e.g. using liquid cooled bearing housings and/or air cooled motor housing and bearings.
However, there is a need in the art for simplified solutions for cooling the bearings of a centrifugal separator.